The vital staining of normal and malignant cells. I.-Vital staining with trypan blue, and the cytoplasmic inclusions of liver and kidney cells

Abstract AIthough intra-vitam staining has now become a routine method in histology, the application of this technique to the special problems of the cell is com­paratively recent. Vital staining has been fully discussed by von Möllendofff (1920, '21, '23, '26). Full references to the literature, and the main results of vital staining, are to be found in his valuable reviews, in which he lays down the fundamental principles of the subject. There are two chief methods of vital staining. Either the dye can be injected into the body of the living animal—intra-vitam staining; or fragments of living tissue cab be removed from the animal and immersed in dilute solutions of the dye—supra-vital staining. with basic dyes the latter method is usually employed owing to the difficulty of retaining the dye in fixed preparations. Basic dyes are also used intra vitam, but most are more toxic than acid dyes. Whichever method is employed, with basic dyes, in general, there is an actual staining of pre-formed structures. Most investigators are in agreement that it is only non-living granules, or droplets, within the cytoplasm that are stained with basic dyes.